Do a test. Play some sort of music trough your headphones. Does it sound good? Probably. So the problem is your other gear, mainly your amp. You would be much better of getting some sort of modeling multifx unit or some plugins for pc and an audio interface. And you might also want to tweak your settings until it sounds better. But dont expect to much, you cant get very far with bad cab emulation.

My Superlux HD 681 was kinda cheap, and I expect it is pretty bad - it also seems like it is beginning to scratch sometimes.

So my question is: What headset should I use? I almost never play electric guitar without headphones because of the noise.

My gear is the following:- Jackson JS32T Kelly- Line 6 Spider 15w

I dont want to pay too much for headphones, but I also want something that can keep up on my gear.

What should I be looking for?

Thanks!

We have had a lot of these "headphones for amp" threads recently. Do a little bit of searching.

I do think your main "problem" is the Spider as we stated in your other thread. I would suggest not to put any more money in your current setup and save for something more professional. If you are able to get by with your headphones, as any "bad sounds" are probably more due to the amp rather than the headphones, then do that. If not, AKG K240 Studio are solid cans that should give you a fairly flat, honest response and they have professional uses as well.